Perfect if and only if Triangular

Similar documents
On the Sum of Corresponding Factorials and Triangular Numbers: Some Preliminary Results

Chapter 1. Number of special form. 1.1 Introduction(Marin Mersenne) 1.2 The perfect number. See the book.

M381 Number Theory 2004 Page 1

Math Circle Beginners Group February 28, 2016 Euclid and Prime Numbers Solutions

Intermediate Math Circles March 6, 2013 Number Theory I

a the relation arb is defined if and only if = 2 k, k

On arithmetic functions of balancing and Lucas-balancing numbers

Numbers and their divisors

Greatest Common Divisor MATH Greatest Common Divisor. Benjamin V.C. Collins, James A. Swenson MATH 2730

A Review Study on Presentation of Positive Integers as Sum of Squares

Definition 6.1 (p.277) A positive integer n is prime when n > 1 and the only positive divisors are 1 and n. Alternatively

Math Circle Beginners Group February 28, 2016 Euclid and Prime Numbers

The Fundamental Theorem of Arithmetic

All variables a, b, n, etc are integers unless otherwise stated. Each part of a problem is worth 5 points.

When is n a member of a Pythagorean Triple?

An integer p is prime if p > 1 and p has exactly two positive divisors, 1 and p.

Introduction to Number Theory

Solutions to Practice Final

MATH 361: NUMBER THEORY FOURTH LECTURE

Proof of the Fermat s Last Theorem

5: The Integers (An introduction to Number Theory)

CHAPTER 1 REAL NUMBERS KEY POINTS

On the Cardinality of Mersenne Primes

PELL S EQUATION NATIONAL INSTITUTE OF TECHNOLOGY ROURKELA, ODISHA

Number Theory and Graph Theory. Arithmetic functions and roots of unity

Numbers. 2.1 Integers. P(n) = n(n 4 5n 2 + 4) = n(n 2 1)(n 2 4) = (n 2)(n 1)n(n + 1)(n + 2); 120 =

= 1 2x. x 2 a ) 0 (mod p n ), (x 2 + 2a + a2. x a ) 2

Friend of 38 JAGST Vol. 14(1) 2012 NECESSARY CONDITIONS FOR EXISTENCE OF A FRIEND OF 38

Some Perfect Pythagorean Triangles Where Their Perimeters Are Quarternary Numbers

The Abundancy index of divisors of odd perfect numbers Part III

Perfect Numbers and Perfect Polynomials: Motivating Concepts From Kindergarten to College

NOTES ON SIMPLE NUMBER THEORY

MATH 4400 SOLUTIONS TO SOME EXERCISES. 1. Chapter 1

. In particular if a b then N(

Perfect Numbers in ACL2

CHAPTER 6. Prime Numbers. Definition and Fundamental Results

Course MA2C02, Hilary Term 2013 Section 9: Introduction to Number Theory and Cryptography

On the Composite Terms in Sequence Generated from Mersenne-type Recurrence Relations

Beautiful Mathematics

Carmen s Core Concepts (Math 135)

Intermediate Math Circles February 14, 2018 Contest Prep: Number Theory

SOLUTIONS TO PROBLEM SET 1. Section = 2 3, 1. n n + 1. k(k + 1) k=1 k(k + 1) + 1 (n + 1)(n + 2) n + 2,

Number Theory Basics Z = {..., 2, 1, 0, 1, 2,...} For, b Z, we say that divides b if z = b for some. Notation: b Fact: for all, b, c Z:

The Chinese Remainder Theorem

Chapter 5: The Integers

not to be republished NCERT REAL NUMBERS CHAPTER 1 (A) Main Concepts and Results

ALGEBRA. 1. Some elementary number theory 1.1. Primes and divisibility. We denote the collection of integers

Number Theory Marathon. Mario Ynocente Castro, National University of Engineering, Peru

SEVENTH EDITION and EXPANDED SEVENTH EDITION

Course 2BA1: Trinity 2006 Section 9: Introduction to Number Theory and Cryptography

Exercises Exercises. 2. Determine whether each of these integers is prime. a) 21. b) 29. c) 71. d) 97. e) 111. f) 143. a) 19. b) 27. c) 93.

On New Identities For Mersenne Numbers

7. Prime Numbers Part VI of PJE

Theory of Numbers Problems

2. THE EUCLIDEAN ALGORITHM More ring essentials

Chapter 2. Divisibility. 2.1 Common Divisors

Junior Villafana. Math 301. Dr. Meredith. Odd Perfect Numbers

COMP Intro to Logic for Computer Scientists. Lecture 15

Analytic Number Theory Solutions

Before we talk about prime numbers, we will spend some time with divisibility because there is

On Exponentially Perfect Numbers Relatively Prime to 15

Factorization of Large Numbers via Factorization of Small Numbers

Corollary 4.2 (Pepin s Test, 1877). Let F k = 2 2k + 1, the kth Fermat number, where k 1. Then F k is prime iff 3 F k 1

PRACTICE PROBLEMS: SET 1

1 Take-home exam and final exam study guide

CHAPTER 3. Congruences. Congruence: definitions and properties

Number Theory Marathon. Mario Ynocente Castro, National University of Engineering, Peru

Perfect Polynomials. modulo 2. Ugur Caner Cengiz. Lake Forest College. April 7, 2015

Know the Well-ordering principle: Any set of positive integers which has at least one element contains a smallest element.

On the number of semi-primitive roots modulo n

p-adic Continued Fractions

Favorite Topics from Complex Arithmetic, Analysis and Related Algebra

On the Prime Divisors of Odd Perfect Numbers

SIX PROOFS OF THE INFINITUDE OF PRIMES

Homework 3, solutions

Number Theory. Jason Filippou UMCP. ason Filippou UMCP)Number Theory History & Definitions / 1

1. Factorization Divisibility in Z.

Table of Contents. 2013, Pearson Education, Inc.

k, then n = p2α 1 1 pα k

Executive Assessment. Executive Assessment Math Review. Section 1.0, Arithmetic, includes the following topics:

Finite Fields. Mike Reiter

Discrete Math, Second Problem Set (June 24)

PUTNAM TRAINING NUMBER THEORY. Exercises 1. Show that the sum of two consecutive primes is never twice a prime.

arxiv: v1 [math.nt] 29 Feb 2016

Notes on Systems of Linear Congruences

2 Arithmetic. 2.1 Greatest common divisors. This chapter is about properties of the integers Z = {..., 2, 1, 0, 1, 2,...}.

Number Theory and Graph Theory. Prime numbers and congruences.

Complex numbers, the exponential function, and factorization over C

NONEXISTENCE OF ODD PERFECT NUMBERS OF A CERTAIN FORM

MATH 2112/CSCI 2112, Discrete Structures I Winter 2007 Toby Kenney Homework Sheet 5 Hints & Model Solutions

Chapter 5.1: Induction

Introduction to Decision Sciences Lecture 10

Pyramid Mysteries. Ehrhard Behrends

Divisibility in the Fibonacci Numbers. Stefan Erickson Colorado College January 27, 2006

Math 118: Advanced Number Theory. Samit Dasgupta and Gary Kirby

2013 University of New South Wales School Mathematics Competition

Worst-case analysis of Weber s GCD algorithm

5.2. Perfect Numbers Divisors of a natural number were covered in Section 5.1.

Introduction to Abstract Mathematics

Transcription:

Advances in Theoretical and Applied Mathematics ISSN 0973-4554 Volume 1, Number 1 (017), pp. 39-50 Research India Publications http://www.ripublication.com Perfect if and only if Triangular Tilahun Muche, Mulatu Lemma, George Tessema and Agegnehu Atena Department of Mathematics, Savannah State University, Savannah, GA, 31404, U.S.A. Abstract A number n is perfect when σ(n) = d = n. It was Euclid who 0 d n d n proved that if ( k 1) is a prime number, Mersenne prime, then N = k 1 ( k 1) is an even perfect number. Moreover, if N is an even perfect number then N = T m for some m N and m 3 is a triangular number m where T m = i=1 i. In this paper we proved the necessary and sufficient condition for an even triangular number T m to be a perfect number N= k 1 ( k 1)besides T m 4 mod 10 and T m mod 10. Keywords: Perfect Numbers, Triangular Numbers and Mresenne Primes. Mathematical subject Classification: 11B7, MSC 010 INTRODUCTION A Perfect Number is a positive integer with the property that it coincides with the sum of all its positive divisors other than the number itself [1]. Thus, an integer n 1 is a perfet number if 0 d<n d n d = n

40 Tilahun Muche, Mulatu Lemma, George Tessema and Agegnehu Atena The nth triangular number is the number of dots composing a triangle with n dots on a side, and is equal to the sum of the n natural numbers from 1 to n. [] n i = i=1 n(n + 1) Example 1: Triangular Numbers: 1, 3, 6,10,15,1,8,36,45... Perfect Numbers: 6, 8,496, 816, 33550336, 8589869056,13743869138, 3058430081399518, 6584559915698317446546961595384176,... The number 6 is unique in that 6 = 1 + + 3 where 1, and 3 are all of the proper divisors of 6. The number 8 also shares this property, for 8 = 1+ +4 +7 + 14. These perfect numbers have been a great deal of mathematical study- indeed, many of the basic theorems of numbers theory stem from the investigation of the Greeks into the problem of perfect and Pythagorean numbers. The Pythagoreans introduced the name perfect and there are speculations that there could be religious or astrological origins because the earth was created in 6 and the moon needs 8 days to circle the earth, mystical associations are natural. The early Hebrews also studied perfect numbers [3]. Definition 1: The sum of divisors is the function σ(n) = the positive divisors of n including 1 and n itself. d n d, where d runs over Definition : The number n is called perfect if σ(n) = n, when σ(n) < n we say n is deficient, σ(n) > n we say n is abundant. Example : 6 and 8 are perfect as σ(6) = 1 + + 3 + 6 = 1 = (6) and σ(8) = 1 + + 4 + 7 + 14 + 8 = 56 = (8).

Perfect if and only if Triangular 41 Euclid was the first mathematician who categorized even perfect numbers. He noticed that 6= 1. 3 1 = 1 ( 1) 8 =. 7 = ( 3 1) 496 = 16. 31 = 4 ( 5 1) 816 = 64. 17 = 6 ( 7 1) Theorem 3 (Euclid)[4,9]: If ( n 1) is prime then N = ( n 1) is perfect. Proof: The only prime divisors of N are ( n 1) and. Since ( n 1) occurs as a single prime, we have that σ( n 1)= (1 + ( n 1))= n, and thus σ(n) = σ ( )σ ( n 1) = ( n 1 1 ) n = n ( n 1) =. ( n 1) = N So N is perfect. Mersenne primes: Monk Martin Mersenne, a colleague of Descartes, Fermat and Pascal created with investigating these unique primes as early as 1644. He knew ( n 1) is prime for n =, 3, 5, 7, 11, 13,17 and 19. [5, 6] Definition 4: A Mersenne prime is a prime number of the form M n = P n 1 where P n is a prime number. Proposition 5:[5] (Cateldi Fermat) If ( n 1) is prime, then n itself is prime. Proof: x n 1= (x 1) (x +... +x + 1). Suppose we can write n = rs where r, s > 1. Then n 1 = ( r ) s 1 = ( r 1)(( r ) s 1 +... + r + 1) so that ( r 1) ( n 1) which is prime, a contradiction. Theorem 6: If N is an even perfect number, then N = ( n 1) where( n 1) is prime. Proof: Since n m = ( n 1)σ(m), every prime divisor of ( n 1) must also divide m, for it is odd and cannot divide n. So, suppose p α divides ( n 1) with p prime.

4 Tilahun Muche, Mulatu Lemma, George Tessema and Agegnehu Atena From the fact that if a b, then σ(a) have, σ(m) a σ(b) b σ(pα ) 1+p+...+ p m pα = p 1 = σ(n) N = σ( )σ(m) n m where equality holds only if a = b we p 1 + p = 1+p p p (n 1)(1+p) n p. Hence = 1 + (n 1) p n p This is only satisfied when the fraction on the right is zero, so that p = ( n 1), = 1 and m = p. Hence N = ( n 1).. Proposition 7: Even perfect number ends in either 6 or 8. Proof: Every prime number p is of the form p = 4m + 3 or p = 4m + 1. In the former case, N = ( n 1) = 4m ( 4m+1 1) = (16) m (. (16) m 1) 6 m ((6) m 1) 6(mod10) Since by induction one can show that 6 m 6(mod10) for all m. Similarly in the latter case, N = ( n 1) = 4m+ ( 4m+3 1) = 4(16) m (8. (16) m 1) (4)(6)(8(6) 1) 4(8 1) 8(mod10). Finally, if n =, N = 1 ( 1) = 6 and so we have the result that even perfect number ends in either 6 or 8. MAIN RESULTS m Let A(x) = i=0 a i x i and B(x) = i=0 b i x i. Then A(x)B(x) = C(x) = n+m k=0 c k x k where k C k = i=0 a i b k i for 0 k m + n. n The decimal expansion of a positive integer N, 0 a k < 10 where a 0 is the unit digit of N is given by N = A(10) = a m 10 m + a m 1 10 m 1 +... + a 1 10 1 + a 0 10 0 = (a m a m 1 a m... a 1 a 0 ) 10 = m i=0 a i 10 i

Perfect if and only if Triangular 43 Theorem 8 [7]: A triangular number T m = i=1 i is even if and only if m = (4k 1) or m = 4k for some ε Z +. m Theorem 9: Even triangular numbers T m end not with or 4. That is neither T m 4 mod 10 nor T m mod 10. Proof: Suppose T m is an even triangular number. Then either m = (4k 1)or = 4k. a) Suppose m = 4k 1. This implies T m = T 4k 1 = (4k 1)( 4k) = 4k 1 i=1 i = k( 4k 1). LetA (10) = k = m i=0 a i 10 i = (a m a m 1 a m... a 1 a 0 ) 10 be decimal expansion of the factor(k) of an even triangular number T 4k 1 where the unit digit a 0 { 0,, 4, 6, 8}. Let b 0 be the unit digit of the factor B(10) = (4k 1) of T m where the decimal expansion is B(10) = 4k 1 = n i=0 b i 10 i = (b n b... b 1 b 0 ) 10. Consider T m = T 4k 1 = (k)(4k 1) = (k)( (k) 1) = A(10) B(10) = ( m i=0 a i 10 i ) ( n i=0 b i 10 i ) = C(10) n+m = i=0 c i 10 i = (c m+n c m+ c 1 c 0 ) 10 The constant term c 0 of C(10) = T m = T 4k 1 is c 0 = a 0 b 0. We consider each unit digit a 0 { 0,, 4, 6, 8} of k = A(10) to determine unit digits b 0 of B(10) = (4k 1) and c 0 of C(10). 1) a 0 = 0 c 0 = 0 ) a 0 =, b 0 = * 1 = 3 c 0 = 6 3) a 0 = 4, b 0 = *4 1= 7 a 0 b 0 = c 0 = 8 (Because (4)*(7) = 8 = 10 1 + 8 10 0 ) 4) a 0 = 6, b 0 = 1, because *6 1 = 11 = 1 10 1 + 1 10 0 c 0 = 6 5) a 0 = 8, the unit digit b 0 = 5 because *8 1 = 1 5 = 1 10 1 + 5 10 0 c 0 = 0.

44 Tilahun Muche, Mulatu Lemma, George Tessema and Agegnehu Atena b) Form = 4k, in similar approach one can show that an even triangular number T m has the following sequence of unit digits. Hence if a triangular number is even, then its unit digit is either 0, 6 or 8 but not and 4. This implies T m 4 mod 10 and T m mod 10. Proposition 10 [8]: Every even perfect number ends in either 6 or 8. Theorem 11: An even triangular number T 4k for each k 1cannot be written in the form of ( n 1) for any n.

Perfect if and only if Triangular 45 Proof: Suppose T 4k = and k 1. Then, 4k( 4k+1) = k( 4k + 1) = ( n 1) for some n k( 4k + 1) = ( n 1) iff 4k + k = n ( n 1) 4k + k - n ( n 1) = 0 (4k ( n 1))(k + n )= 0 4k = n 1 or k + n = 0 k = n 1 (not an integer) or k = n (not a positive integer) k ε Hence T 4k ( n 1) for any k 1 and n. Corollary 1: If an even triangular number T m is perfect, then m = (4k 1) for some k 1. 6 10 8 36 66 78 10 136 190 10 76 300 378 406 *3 *5 4*7 4*9 6*11 6*13 8*15 8*17 10*19 10*1 1*3 1*5 14*7 14*9 t 3 t 4 t 7 t 8 t 11 t 1 t 15 t 16 t 19 t 0 t 3 t 4 t 7 t 8 1 ( 1) 3 1 ( 3 1) 4 1 ( 4 1) 496 58 630 666 780 80 946 990 118 1176 136 1378 1540 1540 16*31 16*33 18*35 18*37 0*39 0*41 *43 *45 4*47 4*49 6*51 6*53 8*55 8*57 t 31 t 3 t 33 t 36 t 35 t 40 t 37 t 44 t 39 t 48 t 41 t 5 t 43 t 56 5 1 *( 5 1) Table III: Even Triangular Numbers with some in ( n 1) form.

46 Tilahun Muche, Mulatu Lemma, George Tessema and Agegnehu Atena Theorem 13: An even triangular number T m is perfect if and only if m = ( t 1) for some prime number t. Proof: A triangular number T m is even if and only if either m = (4k 1) or m = 4k for some k 1 and an every prime number p > is of the form p = (4l + 3) or p = 4l + 1. [7] Suppose T m is perfect. This implies T m = ( n 1) and ( n 1) is prime. But ( n 1) prime only if n is prime number. By (Theorem 11) and the later remark above the only choice for m is m = (4k 1) = 4(k 1) + 3 = 4l + 3 but not m = 4k. m 4k 1 Hence, T m = i=1 i = i=1 i = (k)(4k 1) = ( n 1) and T m = ( n 1) ( 4k 1)(k) = ( n 1) (1) It is easy to show that gcd(k, 4k 1) = gcd (,, n 1) = 1 We use () to show that (4k 1 ) = ( n 1). = gcd(k, n 1) = gcd(, 4k 1). () Because ( n 1)is prime, either gcd (4k 1, n 1) = 1 or ( n 1) (4k 1 ). If the former is true, incorporating with what we have in (), gcd(k, 4k 1) = gcd (,, n 1) = 1 = gcd(k, n 1) = 1 = gcd(, 4k 1) = gcd (4k 1, n 1) = 1 and is clear to see that (4k 1) = ( n 1) and then k =. If the later holds, then there exists d Z + such that (4k 1) = d( n 1). (3) As (4k 1) and ( n 1) are both odd, this implies d is an odd integer too. Substituting (3) into (1) we have, ( 4k 1)(k) = (k) ( n 1) d= ( n 1). This implies (k) d = and either d = k factors of Q d = k Z+ or d = k Z+ and is an even integer for the only are multiples of, which is a contradiction to d is an odd integer.

Perfect if and only if Triangular 47 Hence( n 1) (4k 1 ) only when d = 1 and hence (4k 1) = ( n 1) and k =. Consequently, (k)( 4k 1) = ( n 1) ( 4k 1) = ( n 1)and k = 4k = n and k = n k = n for some prime n. Thus m = 4k 1 = n 1 = ( n 1), and if an even Triangular number T m is perfect, m = ( t 1) for some prime number t. Alternative proof: (k)(4k 1) = ( n 1) 8k k = ( n 1) 4k k = n ( n 1) 4k k - n ( n 1) = 0 4k k - n ( n 1) = 0 4k n k + ( n 1)k - n ( n 1) = 0 4k(k n ) + ( n 1)(k - n ) = 0 (k n )(4k + n 1) = 0 k = n or 4k = 1 n k = n or k = n = (1 n ) k = n or k = n. k ε (because (1 n ) < 0, n 3 and k = 1 n Z + ). Consequently, m = 4k 1 = 4( n ) 1= ( n 1), where n is prime. Conversely, suppose T m is an even triangular number where m = ( t 1) for some prime number t. Then T m = T t 1 = t 1 i=1 i = (t 1 )( t 1+1) = ( t 1 )( t 1 ) = N and which is perfect. Corollary 14: An even triangular T M is perfect if and only if M is a Mersenne prime. Theorem 15: An even triangular number T 4k 1 is not perfect if k 1 mod 5 or k 0 mod 5. Proof: Consider an even triangular number T 4k 1. Suppose k 1 mod 5 or

48 Tilahun Muche, Mulatu Lemma, George Tessema and Agegnehu Atena k 0 mod 5. Then k 1 mod 5 if 5 (k 4) if and only if k = 4 + 5t for some t Z +. Hence T 4k 1 = T 4( 4+5t) 1 = T 15+0 t = = 0(3+4t)(4+5t) if and only if k 4 mod 5 if and only ( 15+0t)( 0t+16) = 10( 3 + 4t)( 4 + 5t) and 10 T 4k 1. Consequently T 4k 1 is not a perfect number. (Proposition 10). Similarly if perfect. k 0 mod 5 one can show that 10 T 4k 1 which implies it is not Theorem 16 : If a triangular number T m is perfect, then T ( n 1) = T (n+1 ) - 3 T ( ) ( ) = (k 1) 3 k=1. Proof: If a triangular number T m is perfect then m = ( n 1) where n is a prime number (Theorem 13). T n = n i=1 i 3 = ( n(n+1) ). T (n+1 ) n+1 ( ) = i 3 = ( ( i=1 n+1 ) ( (n+1 ) +1) ) = (n+1) ( (n+1 ) +1) 4 = ( n+1 + 1) and (4) T ( ) ( ) = i 3 = ( ( i=1 ) ( ( ) +1) ) = () ( ( ) +1) 4 = (n 3) ( ( ) + 1) 3 T ( ) = 3. (n 3) ( ( ) + 1) = n ( ( ) + 1) (5)

Perfect if and only if Triangular 49 Combining (4) and (5) we have, T (n+1 ) - T ( ) = () ( (n+1 ) + 1) - n ( ( ) + 1) = ( ) (( (n+1 ) + 1) ( ( ) + 1) ) = ( ) (( n+1 +. (n+1 ) + 1) 1 ( +. ( ) + 1)) = ( ) (( n+1 +. (n+3 ) + 1 ) - 1 ( + (n+1 ) + 1)) = ( ) ( n+1 + (n+3 ) + 1 n (n+3 ) ) = ( )( n+1 n 1) = ( )(. n n 1) = ( )( n 1) = n ( n 1) = T ( n 1) (6) ( ) Next we show that, T ( n 1) = (i 1) 3 T ( n 1) = T ( n+1 ) - 3 T ( ) n+1 ( ) i=1. ( ) = (i) 3-3 (i) 3 i=1 i=1 = (1 + 3 + 3 3 + + ( (n+1 ) ) 3) - 3 (1 + 3 + 3 3 + + ( ( ) 3 ) ) = (1 + 3 + 3 3 + + ( (n+1 ) ) 3) - ( 3 + 4 3 + 6 3 + + ( (n+1 ) 3 ) ) = (1 + 3 + 3 3 + 4 3 + 5 3 + 6 3 + 7 3 + 8 3 + + ( n+1 3 ) + ( (n+1 ) 3 1) + ( n+1 3 ) ) - ( 3 + 4 3 + 6 3 + 8 3 + ( n+1 3 ) + ( n+1 3 ) ) = (1 + 3 3 + 5 3 + 7 3 + + ( (n+1 ) 1) 3) = (1 + 3 3 + 5 3 + 7 3 + + (. ( ) 3 1) ) = (1 + 3 3 + 5 3 + 7 3 + + (k 1) 3 ) where k = ( ) ( ) = (k 1) 3 k=1 This implies T n 1 = ( k=1 (k 1) 3. (7) )

50 Tilahun Muche, Mulatu Lemma, George Tessema and Agegnehu Atena From (6) and (7) it follows, T ( n 1) = T (n+1 )- 3 T ( ) ( ) = (k 1) 3 k=1. REFERENCES [1] Vladimir, S., (010), On Perfect and Near-Perfect Numbers, ArXiv.org.math.arXiv: 1011.6160, Mathematics, Number Theory. [] David, M. Burton, Elementary Number Theory, University of New Hampshire, Allyn and Bacon, Inc. Boston, 1980. [3] Stan Wagon, Perfect numbers, Math. Intelligencer 7 (1985), 66 68. [4] G.H. Hardy, and E.M., Wright, An introduction to theory of Numbers. Fourth edition, 1975, Oxford University Press, Ely House, London W. 1. Mersenne Prime Search, http://www.mersenne.org/ Mersenne Primes: History, Theorems and Lists http://primes.utm.edu/mersenne. [5] Muche, T., and Atena A., (106), Investigating Triangular Numbers with greatest integer function Sequences and Double Factorial, APJMR Vol. 4,134-14. [6] Bhabesh D. (013). Some aspect of Perfect Numbers and Generalized Perfect. International Journal of Mathematical Archive-4(6), 013, 118-13. [7] Nihal B., and Recep G., (010). On Perfect Numbers and their Relations. Int. J. Contemp. Math. Sciences, Vol. 5, 010, no. 7, 1337 1346. [8] Azizul H., and Himashree K., (014). Generalized Perfect Numbers Connected with Arithmetic Functions. Math. Sci. Lett. 3, No. 3, 49-53 (014). [9] The on-line encyclopedia of integer sequences. http://www.research.att.com /njas/sequences.